In this post from September 2, you may have learned that opponents are hitting .112 off of Antonio Bastardo. That, of course, would be the lowest BAA in baseball history among pitchers with at least 50 innings of work. Saber-minded people wonder, though, if that .142 BABIP of his is sustainable. Pitcher BABIP tends regress to .300 over larger sample sizes, so we would expect the same of Bastardo going forward, right?

Not so fast. While Bastardo is certainly the benefactor of some good batted ball fortune, that doesn’t explain all of it. Bastardo’s batted ball splits are enlightening: 59 percent fly balls, 27 percent ground balls, and 14 percent line drives. So, a fly ball specialist. But wait, there’s more! Of those fly balls, 22 percent stay in the infield.

For a pitcher, infield flies are extremely useful. Very rarely can runners advance and they never become home runs. And, as Rich Lederer found, they are converted into outs 99 percent of the time. Among pitchers with 50+ innings, Bastardo has the best infield fly ball rate in baseball.

It is true that, compared to the league, Bastardo has been fortunate on ground balls and line drives. Bastardo’s ground ball BABIP is .133 lower than the league average; his line drive BABIP is .238 lower. However, he has allowed only 29 and 19 of each, respectively. The difference accounts for an extra 8-9 hits, which would have brought his BAA up to .162.

Meanwhile, Bastardo has allowed 60 fly balls, 22 percent of which (13) are infield fly balls. His overall fly ball BABIP is .067 below the league average. Adjusting only his outfield flies (assuming all infield flies should have been outs), he hasn’t prevented fewer hits than expected (6).

So, when we account for Bastardo’s excellent propensity to induce weak fly balls, his BABIP doesn’t rise too much over what it is now. The real question, though, is if Bastardo can maintain the infield fly ball rate. As the league becomes more familiar with him and his tendencies are revealed, it may be harder for him to have as much success. But as of right now, Bastardo is doing a fine job of making Major League hitters look foolish.